All medications must be tested before doctors can prescribe them to patients. This testing happens in clinical studies, also called clinical trials, in which patients who take part help improve healthcare. The clinical study process happens in 3 main phases:
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Phase 1 trials: These early studies test whether a drug should be given by mouth, injected into the blood, or injected into the muscle. They also test how often the drug should be taken and what dose is safe. A Phase 1 trial usually enrolls only a small number of patients.
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Phase 2 trials: A Phase 2 trial further tests the safety of the drug, and begins to test how well it works. Phase 2 studies usually include patients with a certain disease.
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Phase 3 trials: These studies test a new drug compared with the standard therapy. A participant will usually be randomly assigned to take the standard therapy or the new drug. Phase 3 trials often enroll large numbers of people and may take place at many doctors' offices, clinics, and study sites.
